The field of the invention is systems and methods for magnetic resonance imaging (“MRI”). More particularly, the invention relates to systems and methods for correcting frequency drifts and associated errors in real-time during an MRI scan.
Pulse sequences with high gradient duty cycles can produce heating that, in turn, leads to a gradual drift in the resonance frequency. Frequency fluctuations can also be caused by subject respiration and motion. Volumetric navigators (“vNavs”) based on 3D-encoded EPI for tracking subject motion can be used when embedded in 3D-encoded morphometry scans. Paired vNavs with shifted echo times can be used for frequency and shim correction. These sequences, however, require additional scan time.
It would therefore be desirable to provide a system and method that allows the shift in resonance frequency, or frequency drift, to be measured reliably from a single vNav without expending any additional scan time.